Tension device for sewing machines



Sept. 20, 1938. D. H. CHASON TENSION DEVICE FOR SEWING MACHINES FiledApril 21, 1936 \II. fijl "a 35 adjusting nut. well known multiple spiralscrew threads, in the 35 Patented Sept. 20, 1938 g 2,131,005

UNITED STATES PATENT OFFICE TENSION DEVICE FOR SEWING MACHINES Daniel H.Chason, Elizabeth, N. J., assignor to The Singer Manufacturing Company,Elizabeth, N. J., a corporation of New Jersey Application April 21,1936, Serial No. 75,524

6 Claims. (01. 242-450) This invention relates to sewing machines andand inclined tongue 24, the purpose of which will more particularly toan improved device for tenbe hereinafter described. sioning theneedle-thread. Seated against one of the shoulders of the en- One of theobjects of this invention is to prolarged portion 25 of the arbor I3 isthe usual ten 5 vide an improved means for adjusting the initial siondisk 26 and adjacent the disk 26 is a second 5 tension on the spring soas to meet the minimum tension disk 21, both disks being provided with arequirement. Another object of the invention is central aperture whichreceives the arbor I3, said to provide improved means for adjusting theinidisks having their peripheral portions bent in optial tension on thecheck-spring. posite directions so as to form a peripheral grooveAnother object of the invention is to provide to receive theneedle-thread. Abutting the disks 10 a threading device whichfacilitates the placing of 25 and 21 is a guard-plate 28 having aforwardly the thread between the tension-disks. extending portion 29which enters an aperture in With the above and other objects in view, asthe head of the machine (Fig. 3). Bearing will hereinafter appear, theinvention comprises a nst t e u d-p a 2B is the pp the devices,combinations, and arrangements of member 30 having a centrally locatedraised porparts hereinafter set forth and illustrated in the tion 3| anda diameter bar 32 passing through accompanying drawing of a preferredembodithe slot 33 in the arbor I3. The usual beehive ment of theinvention, from which the several pr g 34 encircles the arbor and itsbase bears features of the invention and the advantages atagainst thecup-shaped member 30 and its other tained thereby will be readilyunderstood by those nd engages an anchor disk 35 formed with an 20skilled in the art, upstanding stop-lug 36 and a diameter bar 31 ofFigure 1 is a side elevation of a portion of a less width than the widthof the slot 33 in the sewing machine bracket-arm' provided with a arbor.tension device embodying my invention. Mounted on the arbor I3 and intelescopic rela- 5 Figure 2 is a side elevation of my improved tion withthe member 30 is a second cup-shaped tension device, a portion of thebracket-arm bemember 38 haVing indieie On its Outer P p y ing shown insection. which cooperate with the pointer 39 on the mem- Figure 3 is alongitudinal vertical section ber to indicate the degree of tension onthe through the tension device. thread. The member 38 is formed with aplurality 30 Figure 4 is a disassembled perspective view of of apertures40 in its base portion and a lug 4| 30 the device. which cooperates withthe stop-lug 36 on the Figure 5 is a sectional View taken along the lineanchor disk to limit the movement of the mem- 5-5 of Figure 2. ber 38 toone complete rotation.

Figure 6 is a longitudinal section through the The free end of the arborI3 is formed with the Th holl w-head In of the usual bracket-arm presentinstance sextuple threads, and the adis formed with a recess II and anaperture I2 lusting nut 42 is correspondingly tapped in order whichreceives the hollow cylindrical arbor I3 of o ece ve t e of the AS Shownin the tension device, the shank being adjustably 6, the lead of thethreads is equal to the distance held in position by the set-screw I4(Fig. 2). P. and th re r ne c mpl t ro ti n of the 40 Coiled about thearbor I3 is the usual torsion dju n nut 42 mOVeS the nut longitudinallyof check-spring I5, the end I6 (Fig. 3) of which i the arbor I3 adistance equal to the lead of the anchored in one of the eight slots II'formed in thr eads- This construction permits a beehive the periphery ofthe enlarged portion 25 of the spring of the usual strength andstiffness to be arbor l3. The other end I8 of the torsion checkused g 23 2 device in the adjust- 45 ing nu is imi e 0 one comple e rotation.zgig f fiig z f i gz i g jgg rg 422 in the presint instance the nut 42is provided wi h a stud 3 which is adapted to enter one of Fcheckfsprfng 1S hmlted m Its of the apertures 40 in the member 38. Thisconmovement m one dlrectlon by the stop'lug struction causes the member38 to rotate with 50 formed on the plate 20 which is adjustably sethenut 42 and permits adjustment so that the cured to the head of themachine by the screw 2| tm t i n on the beehive spring 34 may be andslot 22. obtained.

The plate 20 is also formed with a backwardly Disposed in a longitudinalaperture in the arbor extending portion 23 and a forwardly extending I3for endwise movement is a tension-release pin 55 45, one end of which isadapted to engage the diameter bar 32 of the member 3|] and push thelatter in a direction to relieve the tension disks 26 and 21 of thepressure of the spring 34. The pin 45 is moved longitudinally of thearbor by the bar 46 which is actuated by the usual presser-foot liftinglever.

It will be evident from the foregoing that the pressure between thedisks 26 and 21 may be adjusted by rotating the nut 42 together with themember 38 on the arbor l3, and this movement will cause the nut 42 andmember 38 to move the distance of the lead of the threads longitudinalof the arbor for each complete rotation of the nut 42. It will beunderstood that the lug 4| on the member 38 engages the stop 36 of theanchor disk 35 to limit the movement of the nut 42 to one rotation. Thediameter-bar 31 having a width less than the width of the slot 33 in thearbor, the nut 42 may be turned one complete rotation. The tongue 24 onthe guard-plate 20 extends over the edge of the tension disk 26 andterminates intermediate the outer peripheral edges of the tension disks26 and 21. The purpose of this construction is to facilitate the placingof the needle-thread between the tension disks. The threading isaccomplished by placing the thread on the outer surface of the tongue 24and then pulling the thread in such a manner as to cause it 'to slidedown the inclined surface and finally slip over the end of the tongueand between the tension disks 26 and 21.

Having thus set forth the nature of the invention, what I claim hereinis:- v

1. A tension device for sewing machines com prising, an arbor, a pair oftension disks carried by said arbor, two cup-shaped members mounted onsaid arbor and having telescopic cylindrical flanges, one of saidcup-shaped members having a series of apertures in its base portion, andan adjusting nut carried by said arbor and having a pin which is adaptedto enter a selected aperture in said last-mentioned cup-shaped member.

2. A graduated tension device for sewing machines having, alongitudinally slotted supporting arbor, a pair of tension disks, a pairof telescopically arranged tubular members surrounding said arbor, oneof said members being provided with a series of apertures, a springbetween said members, an adjusting nut carried by said arbor and havingmeans adapted to enter a selected aperture whereby the nut and memberare locked together for rotation, and means for limiting said nut andmember to one complete rotation.

3. A graduated tension device for sewing machines comprising asupporting arbor formed with a series of longitudinal slots, acheck-spring coiled about said arbor and having one of its ends anchoredin one of said slots and its other end extending outwardly from thearborin a position to engage the needle-thread, a pair of tension diskscarried by said arbor, telescopic cup-shaped members carried by saidarbor and enclosing a compression type spring, one of said membershaving an indicator and the other of said members being provided Withsuitable indicia which cooperate with said indicator, an adjusting nutcarried by said arbor and means for limiting said nut and one of saidcup-shaped members to one complete rotation.

4. A graduated tension device for sewing machines, comprising asupporting arbor, tension disks carried by said arbor and having theirouter peripheral portions bent in opposite directions, and a platehaving a portion which embraces the arbor, said plate being formed witha tongue having a greater length than the distance between the outerperipheral portions of the disks and which is inclined towards andextends over the edge of one of the disks and terminates intermediatethe outer peripheral edges of the disks for directing a thread betweenthe disks.

5. A tension device for sewing machines, comprising a supporting arbor,tension disks carried by said arbor and having their outer peripheralportions bent in opposite direction to form a peripheral groove, and aplate formed with a backwardly extending portion which carries aforwardly extending tongue which terminates in-f termediate the outerperipheral portions of the disks for guiding thread into the groovebetween said disks, said forwardly extending tongue being inclinedtowards said disks. 7

6. A graduated tension device for sewing machines, comprising asupporting arbor, tension disks carried by said arbor and having theirouter peripheral portions bent in opposite directions to form aperipheral groove, and a plate formed with a tongue which is inclinedtowards said disks and terminates intermediate the outer peripheralportions of the disks for directing a thread into the groove. I a aDANIEL H. CHASON.

